(a) Field of the Invention
The present invention relates to a turbo charge system of an engine. More particularly, the present invention relates to a turbo charge system of an engine that minimizes energy loss of exhaust gas by mounting a crossover pipe that connects exhaust manifolds respectively mounted to cylinder heads at both sides of the engine, and the crossover pipe is formed as a double pipe structure.
(b) Description of the Related Art
Generally, an engine must take in as much air mixture as the exhaust gas amount, but it can actually take in only 80% of the exhaust gas amount. The amount of power an engine produces is proportional to the amount of airflow, and the number of valves may be increased or the diameter of the valves may be enlarged in order to increase the air intake amount. In addition, air may be forcibly blown in by a turbo charger in order to increase air intake amount.
Generally, a turbo charge system increases the air intake amount input to an intake manifold by using a turbo charger connected to the intake manifold and an exhaust manifold. More concretely, in a case in which a turbine of the turbo charger is forcibly rotated by exhaust gas having passed through the exhaust manifold, a compressor connected to the turbine rotates and forcibly blows air into the intake manifold. According to the turbo charge system, the high temperature and pressure exhaust gas passes through the turbine and its temperature and pressure are lowered. Therefore, energy of the exhaust gas is transmitted to the turbine and the turbine is rotated. Hence, if the temperature and pressure of the exhaust gas blown into a turbine housing is increased, the turbo charger will have higher efficiency.
According to a conventional turbo charge system for a multi-cylinder-head engine, an intake manifold and an exhaust manifold are mounted at respective sides of each cylinder head, and the exhaust manifolds are respectively connected to first and second turbo chargers. In addition, the first and second turbo chargers are respectively connected to intake manifolds mounted at each cylinder head. Therefore, when exhaust gas is blown into the first and second turbo chargers from the exhaust manifolds, turbines of the first and second turbo chargers rotate. In this case, a compressor connected to each turbine is rotated by rotation of the turbines and forcibly blows air into the intake manifolds. In addition, the exhaust manifolds are connected to each other by a crossover pipe. Therefore, when the engine is operated at a high speed or a high load condition, both the first and second turbo chargers are operated. On the contrary, when the engine is operated at a low speed or a low load condition, the exhaust gas exhausted from one exhaust manifold is gathered at the other exhaust manifold through the crossover pipe, and the gathered exhaust gas rotates the turbine of one turbo charger of the first and second turbo chargers. Thus, efficiency of the turbo charger is improved.
However, since the crossover pipe is mounted at the exterior of the cylinder head according to the conventional turbo charge system, noise may occur and the outward appearance of the cylinder head may be poor. In addition, since the crossover pipe is tightly bent and a length thereof is long, exhaust pressure loss may occur.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.